The present invention relates generally to microcircuit design techniques and in particular to Josephson junction-type circuits.
The significant development of solid-state electronic microcomponents has recently led to the manufacture of ultra compact circuits using techniques known as large scale integration (L.S.I.) which allows the assembly of a few thousands active components, such as transistors, on a single silicon substrate. This technology has presently to face, in order to reach the next step of very large scale integration (V.L.S.I.), resolution problems for the manufacture of active patterns. Despite the progress made by microphotolithography, specially designing the mask through which exposure of various layers formed on the semi-conductor substrate is carried out, photomicrolithography hardly allows resolution below about the two microns despite theoretical statements announcing that resolutions of about half a micron can be obtained. Designing such masks is carried out by computer controlled electron beams. Once the mask is positioned, the sensitive layer is exposed to radiation or selectively subjected to chemical reaction. Some regions of a silicon layer can thus be selectively transformed into insulating portions by oxidizing silicon into silica.
The field of organic size conductors, and especially uni-dimensioned conductors, has been thoroughly investigated for some time, primarily by research groups to which the present inventors belong, especially as regards super-conducting properties, under certain conditions, of such conductors. The uni-dimensioned organic conductors conduct along one crystal direction only when above a certain temperature below which they are insulators. Low dimension conductors to which the present invention relates can be generically defined as materials showing an open Fermi surface. Quasi-unidimensional conductors (QID) and the alloys thereof specially have a quasi planar Fermi surface. It has thus been found that potentially superconducting organic conductors become insulators when a high transverse magnetic field is applied which field is of about a few Tesla. However, as soon as this magnetic field has been suppressed, the conductor instantaneously reverts to its electrical conducting state.